I have a upload script in another host and after remote file upload with
Error: Permission denied to access property "stopUpload"
You are probably violating Same Origin Policy.
Iframe can access parent window content only if they both belong to same origin.
An origin consists of
domain name(example.com and
port(default 80). If any of these are different then sites are considered from different origins. If you are able to modify content of both the sites then you can manually set the
document.domain=domain.com. After that you won't get the error.
Both the sites should at least have super domain in common for manual domain setting to work.
facebook.com and google.com can never be compatible since their super domains are different.
docs.google.com and developer.google.com can be compatible as they have
super domain google.com in common.
They both would have to declare
document.domain=google.com in a script tag.